This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Following knee and hip replacement, ambulation is often limited by joint pain, greatly decreasing functional mobility, rehabilitation quality, and possibly the ultimate functional outcome. Perineural infusion is a relatively new analgesic technique that involves the percutaneous insertion of a catheter directly adjacent to the peripheral nerves that supply the affected joint. Local anesthetic is then infused via the catheter to provide potent, site-specific analgesia free of significant side effects. The ultimate objective of the proposed research is to determine if perineural local anesthetic infusion in the immediate postoperative period has both short- and long-term benefits following knee replacement surgery for osteoarthritis. The research plan consists of a multicenter, randomized, triple-masked patients, investigators, statisticians, placebo-controlled, parallel-arm clinical investigation. Patients will randomly receive either perineural local anesthetic or normal saline for 4 days following surgery. The primary outcome is the time until three specific, predefined readiness-for-discharge criteria are met following surgery. Secondary outcomes include the relationship between analgesic technique administered in the immediate postoperative period and subsequent pain, stiffness and functional disability.